TireSizesFinder

27x8.50R14 vs 225/70R15

225/70R15 is 0.40 in (10.2 mm) taller than 27x8.50R14, a +1.49% diameter difference. With the speedometer set for 27x8.50R14, an indicated 60 mph is 60.9 mph on 225/70R15.

Is this a safe swap?

Diameter difference +1.49%: within the ±3% guideline

By overall diameter alone, 225/70R15 falls inside the ±3% range commonly used as a guideline when replacing 27x8.50R14. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 27x8.50R14 (27.00 in) vs 225/70R15 (27.40 in)27x8.50R1427.00 in × 8.50 in225/70R1527.40 in × 8.86 in
Side profile and tread width, drawn to the same scale.
27x8.50R14 vs 225/70R15 differences
Measurement27x8.50R14225/70R15Difference% diff
Overall diameter27.00 in (685.8 mm)27.40 in (696.0 mm)+0.40 in (+10.2 mm)+1.49%
Sidewall height6.50 in (165.1 mm)6.20 in (157.5 mm)−0.30 in (−7.6 mm)−4.60%
Section width8.50 in (215.9 mm)8.86 in (225.0 mm)+0.36 in (+9.1 mm)+4.21%
Circumference84.82 in (2,154.5 mm)86.08 in (2,186.5 mm)+1.26 in (+32.0 mm)+1.49%
Revolutions per mile747736−11−1.47%
True speed with the speedometer calibrated for 27x8.50R14
IndicatedActual on 27x8.50R14Actual on 225/70R15Difference
30 mph30.0 mph30.4 mph+0.4 mph
60 mph60.0 mph60.9 mph+0.9 mph
75 mph75.0 mph76.1 mph+1.1 mph

Ride-height change: 225/70R15 raises the vehicle by 0.20 in (5.1 mm) at the axle (half the +10.2 mm diameter difference).

225/70R15 is 0.40 in taller than 27x8.50R14 and 9 mm wider, a 1.49% difference in overall diameter.

With the speedometer calibrated for 27x8.50R14, an indicated 60 mph is actually 60.9 mph on 225/70R15, and revolutions per mile change from 747 to 736.

225/70R15 mounts on a 15-inch wheel, a plus-1 fitment from the 14-inch wheel of 27x8.50R14.

Size pages

Other comparisons with 27x8.50R14

Other comparisons with 225/70R15

Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.